#include "iwth.h"
#include <errno.h>

#ifdef __APPLE__

#ifndef __unused
#define __unused __attribute__((unused))
#endif

int
pthread_barrierattr_init(pthread_barrierattr_t *attr __unused) {
  return 0;
}

int
pthread_barrierattr_destroy(pthread_barrierattr_t *attr __unused) {
  return 0;
}

int
pthread_barrierattr_getpshared(const pthread_barrierattr_t *restrict attr __unused,
                               int *restrict pshared) {
  *pshared = PTHREAD_PROCESS_PRIVATE;
  return 0;
}

int
pthread_barrierattr_setpshared(pthread_barrierattr_t *attr __unused,
                               int pshared) {
  if (pshared != PTHREAD_PROCESS_PRIVATE) {
    errno = EINVAL;
    return -1;
  }
  return 0;
}

int
pthread_barrier_init(pthread_barrier_t *restrict barrier,
                     const pthread_barrierattr_t *restrict attr __unused,
                     unsigned count) {
  if (count == 0) {
    errno = EINVAL;
    return -1;
  }

  if (pthread_mutex_init(&barrier->mutex, 0) < 0) {
    return -1;
  }
  if (pthread_cond_init(&barrier->cond, 0) < 0) {
    int errno_save = errno;
    pthread_mutex_destroy(&barrier->mutex);
    errno = errno_save;
    return -1;
  }

  barrier->limit = count;
  barrier->count = 0;
  barrier->phase = 0;

  return 0;
}

int
pthread_barrier_destroy(pthread_barrier_t *barrier) {
  pthread_mutex_destroy(&barrier->mutex);
  pthread_cond_destroy(&barrier->cond);
  return 0;
}

int
pthread_barrier_wait(pthread_barrier_t *barrier) {
  pthread_mutex_lock(&barrier->mutex);
  barrier->count++;
  if (barrier->count >= barrier->limit) {
    barrier->phase++;
    barrier->count = 0;
    pthread_cond_broadcast(&barrier->cond);
    pthread_mutex_unlock(&barrier->mutex);
    return PTHREAD_BARRIER_SERIAL_THREAD;
  } else {
    unsigned phase = barrier->phase;
    do
      pthread_cond_wait(&barrier->cond, &barrier->mutex);
    while (phase == barrier->phase);
    pthread_mutex_unlock(&barrier->mutex);
    return 0;
  }
}

#endif /* __APPLE__ */

